Apparatus for forming hollow plastic containers with pre-molded finished neck sections



June 14, 1960 M. J. GREBOWIEC 2,940,120

APPARATUS FOR FORMING HOLLOW PLASTIC CONTAINERS WITH FIRE-MOLDEDFINISHED NECK SECTIONS Filed June 1, 1954 4 Sheets-Sheet 1 .37 1 I 55m2} fi /6 25a 1 27 "250 I 29 1 6 W I la June 14, 1960 M. J. GREBOWIEC2,940,120

APPARATUS FOR FORMING HOLLOW PLASTIC CONTAINERS WITH PRE-MOLDED FINISHEDNECK SECTIONS 4 Sheets-Sheet 2 Filed June 1, 1954 I I II IIIAIIIIIIIIIIII z IR 1 z v iw i Q w fi 7/// wmwwww ww m. -W m i w w- A, akm yJune 14, 1960 M. .l. GREBOWIEC 2,940,120

APPARATUS FOR FQRMING HOLLOW PLASTIC CONTAINERS WITH PRE-MOLDED FINISHEDNECK SECTIONS 4 Sheets-Sheet 3 Filed June 1, 1954 i l Q INVENTOR. M/Ma/firebaw/ea BY w June 14, 1960 M. J. GREBOWIEC 2,940,120

APPARATUS FOR FORMING HOLLOW PLASTIC CONTAINERS WITH PRE-MOLDED FINISHEDNECK SECTIONS I Filed June 1, 1954 4 Sheets-Sheet 4 477' ENE).

United States Parent 2,940,120 APPARATUS FOR FORMING HOLLOW PLASTICCONTAINERS WITH PIKE-MOLDED FINISHED NECK SECTIONS Michael J. Grebowiec,Kansas City, Mo., assignor to Injection Molding Company, Kansas City,Mo, a corporation of Missouri Filed June 1, 1954, Ser. No. 433,606

3 Claims. (Cl. 18-5) This invention relates to methods and apparatus forblow molding plastic containers and refers more particularly to suchmethods and apparatus for forming hollow plastic containers or bottleswith pre-molded finished neck sections.

Previously, plastic bottles and containers have been produced by aprocess of extruding a tube of plastic between the halves of a mold froman extrusion head assembly, closing the mold sections on the tube to fixboth ends therein while leaving the tube suspended within the cavity ofthe mold, and then injecting air into the tube to expand it against thewalls of the mold to form a container or bottle of the desired shape.

One of the main objections to this process in its present form is thatwhile the neck portion of the container may be blown formed to theproper outlines as is the rest of the container, it comes out of themold essentially unfinished and with a large amount of excess plasticthereon. Therefore, special operations are required to trim ofi theexcess material (commonly called precutting), core out the neck sectionto the proper internal diameter and face the section to its properheight. It is obvious that these extra operations require additionaltime, handling of containers, and the excess material which is trimmedfrom the original molded neck section is waste and must be reprocessed.Extra machinery and employees to man them as well as factory space forthe placement of the machines are also, of course, required. The extraoperations demanded by the unfinished neck sections, while simple, andof a very prosaic and mechanical nature, requirehandling of thecontainers individually by employees and insertion of the containersinto finishing and facing machines, thus offering the usual statisticalhazards to the employee and possible costs to the employer.

Therefore an object of the present invention is to provide a method offorming plastic containers having pre-molded finishing neck sections.

Another object is to provide a method of forming plastic containershaving pre-molded finished neck sections wherein no finishing operationson the neck portion are required, thereby minimizing expenditures oftime, material and handling by the employees together with eliminatingthe need for extra finishing machines and operators to man them.

Another object is to provide a method of forming plastic bottles whereinplastic is extruded from an extruding head assembly directly into athread die assembly thereby first forming the neck of the container inits final form.

Another object of the invention is to provide a method of formingplastic bottles wherein plastic material is extruded directly into athread die assembly, the thread die assembly then leading a hollow tubeof plastic from the extruding assembly between the halves of a mold, themold halves then being closed on the tube, the bottle or container blownwithin the mold and the container th n released both from the mold andfrom the thread die assembly.

Another object of the present invention is to provide apparatus forforming plastic bottles having pre-molded finished neck sectionscomprising an extruding head assembly to extrude plastic in the form ofa hollow tube,

a thread die assembly movable toward and away from the extrusion headassembly to receive plastic from the extruding head assembly and drawthe hollow tube therefrom, and mold sections adjacent the extruding headassembly movable to enclose the hollow tube when the thread die assemblyis retracted from the extruding head assembly. Y

Still another object is to provide apparatus having the above mentionedparts and an air input in the thread die assembly operable to inject airinto the hollow tube when the tube is enclosed by the mold sections.

Still another object is to provide such described apparatus forproducing plastic containers with pre-formed neck sections wherein thethread die assembly is remove able from the formed neck of the containerand the mold sections retractable from the body of the container afterthe container has been formed or blown in the mold.

Other and further objects of the invention will appear in the course ofthe following description.

In the accompanying drawings which fonn a part of the instantspecifications and are to be read in conjunction therewith, embodimentsof the inventive apparatus and method'are shown and like numerals areused, to indicate like parts in the various views.

Fig. 1 is a side-sectional view of the upper portion of an apparatus forforming blow-molded plastic containers With'pre-molded finished necksections. This view is also intended to illustrate the first stage ofthe inventive method.

Fig. 2 is a side view of the apparatus of Fig. 1 showing a later stagein the operation of the inventive method. Fig. 3 is a side view similarto that of Fig. 2 but 1llus-.

trating a stilllater stage than that shown in Fig. 2 of the inventivemethod.

Fig. 4 is a side view of the apparatus of Fig. 1 but illustrating astage in the inventive method still later than that of Fig. 3.

Fig. 5 is a View taken along lines 5-5 of Fig. 6 in the direction ofarrows.

Fig. 6 is a side view with parts in section of assembled apparatus forblow molding plastic containers with pre-molded finished neck sections.

Referring to the drawings and more particularly to Figs. 1 and 6, theapparatus comprising the present invention and in which the inventivemethod is practiced has three basic part assemblies. These assemblieswill be described separately and comprise; an extrusion head assemblydesigned to extrude a tube of hot semi-fluid plastic material, a threaddie-core assembly adapted to receive plastic material from the extrusionhead assembly and to move toward and away therefrom, and a mold assemblypositioned adjacent the extrusion end of the extrusion head assembly,halves of the mold adapted to move relative the extrusion head assembly.The

fourfigures, as well as showing the parts and details of the apparatus,illustrate various stages of the method in the art. Fig. 6 sho ws thesepart assemblies as mounted 1 on a preferred form of frame. Thesemounting and movframe loEli iiut.

ing means and mechanisms "are not shown in full detail,

that the present invention be restricted to" any particular Y semblie sis set forth but it's'hould be understood that such rnqunting is'not tobe viewed in a limiting sense.

7 v 7, he extrusion head assembly," g i l a The w' 's s h d s i r Wsrdesn e d as fixedly attached to the lower portion of shait 43'andadjusting locknut 45 is adjustably attached to the upper portionthereof. Mandrel pressure spring 46 is engaged between spring retainers40 and 44 and is compressible by movement of mandrel 38 upward. Thetension of spring 46 is, of course, adjustable byrotation oi upperspring retention shaft 43. a l a P n inlet u uin 4 p net a s h ad odrl)as shown. Plastic material is'i'ntroduced into head 19-, or,

more accurately, annulus 32 through inlet 47 from a flow channel'(47Zt..Fig. 5 which is controlled by means Ioj a i e io l neith r t.which latter t uc ures a illustrated, being conventional and wellknownin the '.I'What should merely be noted, for the purposes of thisthis ensign: hest seen in the. portion .offFigure it "llijexti'hsionheadassembly is mounted on diejc arrier frame m h i s wnssc g mefi allr Eis@Fen t me in ebfivef i f: 2 1.12 91 mm :andlow' r add sectlons fl z.andllengagedby a i r i fi l jai i' u s i sad. 1.7- Fixed b tween exusion head leek stirs it 315917 is extiri isio rl'liead assnilbly'supportll8, f h is fixedly at tached to theiextru'sion head asseniblyan d jrig idly supl bfi i amegg s jl'The'' trusion head assembly has ahead body. 1? contaiiiinghead body cavity 20. Bushingi ll ispositionedfadjacent 'the lower end of head body'19 and has'circularorifice. 22 therein. Bushing holder 2 3.circumferentially enclosesbushing 21 and has. adjusting screws 24 piercing its sides abuttingbushing 21. There. are: four adjusting screws 24 positioned'90 degreesof arc apart, so that v the bushing may be'adju sted preciselyfrelativethe head body 191; Bushing holder'clamp ring 25 engages'indentedportions 19:: and 23g of head bj o dy 19 and bushing holdera 2 3 tofixedly attach the bushing and bushingholder tofhead body 191 'shoulderzlgz on bushing 21 engages indented portiofillib ofbushin'g; holdermaintainjverticalien gsgemeator theflbushing'and bushing holder,Spreader. cap "bracket 26" is positioned above 'iiead' body 1 9 isfixedly attachedthereto by spreader cap bracket, screws ZTwIiich enga ethread fibres 19b hadbody 19 aim.

pass through holes '2i6aof the spreader ea flbrsek twhrfi haveenlargedshouldered portions 26b to engage screw 7 heads 27b. Stationaryspreader 2 8 'is mounted inside of portion 528a ofth'estationary-spreaden 'Annulus 32 is defined in cavitylt) between theinner wall of head'body 19- and. spreaders ZSWand-SQ; Portions-of thesecondary srir'eadenfiflare supportednextgtothe inner wa l of the a headbody down to the firstangular break point in the.

innerbodyWall. 'Adjustingnut 33, having lower fl ange 34,I is mounted.above thesecondary. spreader 3 0, the'sta tionary. spreader 28. and thespreader capbracket 26. Nut' 33-,is connected with secondary spreaderbylugs 35 which la s o y 19. ju ing. nut ret iner. as is fixedly attachedto spreader. cap. bracket 26 by screwsand dowels.

which are, 11 ttvisllnvtrllt Adjusting nut retainer 36has n hich et s -wtha 1e rotat ry clearance,

flang ed .o f gadjusting;nut} 33. Mandreli 38' is. islidably mountedwithin adjusting nut 33 and secondaryospfeader, Q; .Mead s 2 hasfvlindfical ope in fii in the-lower i t er o endeari re a n r- Q .f medatthe up end 4 thereimto receive upper spring retention shaft 43, which is-.,alsn .threaded therein. Upperspri'ng retainerlt44 is 7 rm im an led.partvhen he iiehq s t 'sub assemblies, the die holder sub-.assenjbly com45 head body ;1 9 and spreader cap bracket gfiis fixedly ait 7 T tachedto the latter by' keys'29. Secondary spreader 3t}. a is mounted withinstationary spreader '28 iandmovably attached thereto by threads 31 whichengagethreaded' 30. The. plastic material enters the cavity 20 orannulus32 through. the inlet and flows around the channels defined by thehead'body 19inner'wa1l and'stationary spreader 30 outer walllfor 90degrees on each side of the spreader 30, when the channels turn sharply90.degrees downwardly and then widen until the two-. channe'ls'v meet ata point opposite the first break inwthe head body inner wallt. As.previously-mentioned, the secondaryspreader is supported. next to'thebody wall down to the aforementioned point.

. The thread die-cafe assembly r he e d. em s em ly sf hn d1fr tn wopsi9 m as pair ofinter-connected die holders C. t'aimngtwq reunifercntialdie members, and thedie-fcjore su sembly, c0m; posedof a die '-c0re,;a;coreholder, a wedgeblock, cams mounted 'on saidjwedge. block, Thesesub-assem-j iss w ll be S rat y d sc b d: a11l 4he il19 di wb ssemb fitie e nsfir s med a, .ha der. i lakass ninzly ehc ds s ay lq s ilmte enuse @15 9 (nata etw he die adders 4 r .1b.$ Q itismasin Figs: .2; iddefinin a i flthere t en D e h w r P eviou l m n bn lbse rstica and;..hen,f .t that,

position, define larger cavity 52 thereb'etw'een. Lower.

ha redf de face 'jnd. enter wa lsfi' z which define cavity 52therebetwe'en (see Fig 2 e holders 48 are pivotally attached at'theg'ujnctures; of arms 4 9" and 51 by pivot pinS}, wl'iitb is iinedlyattached to. rounded bearingfportions 5e and'hasextensions 5'3zzf( see-Fig; 5 Bearing portions: Stare-each formed on an posite die'holder 48;the opposing dieho'lder having hol lowed bearings pace 55 to fit' oveiiand'mate with the opposing'bearing' portion 54'. Pairs of-rollers56"'are rota-F ablymounted on the outer surfaces of side faces .1M.Circurnfei'entialdie members SI-havingflange 58 on the bases thereoftofit into recesses 59in die; no de npper arms 49 are fixedlymountedin;the'upper arms;49*byscrews 64 Thefinner side moldingfacesflofdiametr bers 57 are'configuredgto form the ontline of the'necky sectionof the container which is-to be blow molded; The cavity 62 betweenthetwo faccs -61fis oi-'the-outerdiameter of such-a neck section.- r

Refer-ringfto medic-core sub-assembly, core 63 has base 63a, extension63b, neck section-53c and-nipple-dd as oonstituent parts. Air injectionpassage-64 penefiates all of the sections otcore. 63 set forthhereinbefore..- It

shouldbe notedthatth'e diam'eter of-neck section 63c-is equal. tothe-desired intemal diameter-of the neclp section of thecontainer whichis to be formed. Nccsse'ctipnfib- 7 thereof Mandrel retention armAlisifixedly "mounted, ogadj ting nutjretainer. .36 andhas thfeadedhole"42 and side. faces 61'of circumferential die members'l de- 'finebetweenr'theni an annuluszh'aving. the precise tom-r and structure ofthetnecle section oi the container; Coreholder 65'has slot '66thereindocont-ain pivot pin-53k The length of slot 66 is equivalent tothe;distancebetweenoperation points A-A and 6-0; the signifie'anceof-whi'ch distance will be explained later in connection with theoperation of the apparatus and inventive method. Core holder 65 also hasopening 67 to contain base 63a of core 63. Air injection passageway 64is continued from core 63 and runs the length of core holder 65wherefrom it departs through side opening 68. Wedge block 69 has angledupper edges 70 which mate with outer walls 51b of die holders 48 whenthe latter are in closed position. Block 69 has cavity 71 (Fig. 2)therein to receive in fixed engagement core holder 65, Core 63, coreholders 65 and wedge block 69 are fixedly attached one to the other andmove as a unit, never separating fi'om one another. Air passage 64continues in wedge block 69 mating with the passageway in the core 63and core holder 65. Die holder opening cams 72 are fastened to the sidefaces of wedge block 69 by screws 73 and have slots 74 cut therein.Slots 74 have parallel portions 74a of a length equivalent to thedistance of operation point A-A to B--B. Slots 74 additionally haveangled-in portions 74b having a length vertically equivalent to thedistance from operating point B B to C-C. These operating points, aspreviously mentioned, will be explained in more detail in thedescription of the operation.

The mold assembly The operating portion of the mold assembly is composedof mold halves 75 having inner walls 76, upper walls 77 and lower walls78. Upper walls 77 contain tube gripping portions 79 having a very smallclearance so as to fuse the bottom portions of the molten tube when themold halves close but not to sever the tube inside the mold from thatoutside the mold. Upper walls 77 also have wells EEO-therein to containthe upward extension of the molten tube. Lower walls 78 have angledfaces 81 so configured as to sealedly engage the outer faces ofcircumferential die members 57 when the mold halves are closed. When themold halves 75 are closed against the circumferential die members 57,the continuation of the inner face of lower wall 78 from the inner sidemolding face 61 of the circumferential die member 57 defines the neckand shoulder section outer shape of the container to be formed.

Operation The operation of the method and the interaction of the variousportions of the apparatus will be described in relation to Figures 1through 4.

7 Referring first to Figure 1, the apparatus is shown in startingposition. Note that the thread die-core assembly is positioned adjacentthe extrusion head assembly and, more particularly, the orifice 22 ofthe extrusion head bushing 21. The outside surfaces of thecircumferential die members 57 are juxtaposed against the angledsurfaces of the bushing orifice and the thread die-core 63 is positionedagainst the mandrel 38 and is forcing it into retracted position againstthe action of the spring 46. The nipple 63d on the thread die-core isengaged by the cylindrical hollow orifice 39 in the mandrel to centerthe die-core thereon. Thus the annulus between the secondary spreader 30and the extrusion head bushing 21 and the annulus 63a between the threaddie-core and thread die circumferential members are aligned, one withthe other.

Plastic material is introduced into the head body 19 of the extrusiondie assembly by means of a directional valve, which is not shown. Theplastic material is forced downwardly around the two spreader-s 28 and3t) and through the circular orifice 22 formed by the bushing 21 and thecore-mandrel union into the thread die annulus 63a. The mold sections75, during this portion of the operation, are separated and out ofcontact with either the extrusionhead assembly or the thread dieassembly. The annulus 632 between the thread die core 63 and thecircumferential die members 57 is packed with plastic from the extrusionhead assembly until a predetermined pressure has been attained, at whichtime the thread die core assembly is moved downwardly away from theextrusion head assembly. As the extrusion of plastic material from thebushing orifice continues during the motion of the thread die-coreassembly away from the extrusion head assembly, the result is that ahollow tube of plastic is led downwardly from the extrusion headassembly by the thread die assembly. Preferably, the thread die assemblyis moved downwardly at a rate equal to the rate of extrusion of plasticmaterial from the extrusion head assembly, thus providing an extrudedmolten tube of uniform wall thickness. The thread die assembly leads thehollow tube from the bushing down to position A--A (Fig. 2) preparatoryto blowing. This distance is essentially equivalent to the length of themolds plus the desired clearance distance between the top of the moldand the bottom of the extrusion head assembly.

When position A-A has been reached, the mold sections 75 are closed, asis shown in Fig. 2. The top portions of the mold tightly squeeze thewalls of the tube together to form a seal therebetween as well as togrip the end of the tube. The lower ends of the molds enclose in sealingfashion the outer surface of the thread die circumferential members 57.The lower end of the tube, of course, remains enclosed in the annulus63c between the die-core 63 and the circumferential members 57. When themold sections 75 have closed to sealing position, air is injectedthrough passage 64 in the die-core assembly to blow the bottle anddistend the walls of the tube against the inner walls 76 of the mold.

It should be noted that at the beginning of the motion downward of thethread die assembly, that the mandrel 38 in the extrusion head assemblymoves downwardly with the core 63 until it is flush with the face of thebushing 21. It is desirable to maintain the mandrel 38 in this positionuntil the next contact of the die-core 63 in order to facilitate cutofiof the plastic material from the extrusion head assembly after thebottle is formed and blown. The die holder sub-assembly of theretracting thread die-core assembly, together with the attachedcircumferential die members 57, is stopped from any further downwardmovement at position A-A and moves no further downwardly during the restof the container forming cycle.

Referring now to Figure 3, after the bottle or container is formedwithin the molds 75 by blowing, the core 63, which is secured in thecore holder 65, which in turn is anchored in the wedge block 69, movesdownwardly out of the blown bottle, or, more accurately, the neck of theblown bottle, to position B--B. Position 3-3 is defined as the point atwhich the rollers 56 reach the position in the slots 74 in the cam wherethe slots or cam ways 74 turn inwardly ofi parallel and the die core isout of the container neck section. During the motion from position A-Ato position B-B, the rollers 56 are riding in the camways 74, but, asduring this time the camways or slots 74 are parallel, no force isapplied through the rollers 56 to the die holders 48 and attachedcircumferential die members 57 to move them apart. Thus, during themotion from position AA to position B-B, the circumferential die members 57 continue to fixedly grasp the outer portion of the formed necksection of the container, despite the fact that the die-core 63 is beingwithdrawn therefrom.

When the die core assembly reaches position B-B, the mold sections 75are drawn apart, thus leaving the formed container suspended by the tailof plastic material from the extrusion head assembly and, momentarily,still fixed by the neck in the circumferential die members 57. Althoughthe mold sections are moved apart at positions BB, there is nohesitation of the downward movement of the die-core assembly at positionB--B, and the die-core assembly continues to move downwardly to positionO-.C. Position O-C is defined as thepoint where the rollers 56 on thedie holder assembly reachithe end of: camways or slots: 74 and thedieholder 49' are completely separated with lower armsiil' tween the.niold sections, 75 to carry oii conveyor.

Neither the cutter blade nor the carry oft": conveyor are shown (inFigs. 1 through 4),v as such apparatus is well known; and conventionalin theiart.

the container is ejected, the, dieec'ore. assembly ismoved upwardlybetween the die holders 48, thereby" reversing; the. previouslydescribed cami action, reuniting thc circumferentialjdie members 57 andreassemhling; The; die;

the; thread die assembly into an integral unit. holder sub-assembly ofthe thread die assembly is held at-jzhsitionA-A until the die,v coresubassembly'reaches;

"Two forces act to stop the thread die-core assembly at position A 'A,:(1.) the piston inthe air cylinder 98 is stopped, which stops the diecore'sub-assembly, and (2) pivot pin extension 53:: is capturedin slot101' between arms 102 of stop block 103. Stop block 103 (best seen 7 inFig. is adjustably mounted on pin stop rod 104,

position also, at, which time. the entire assembly 7 continues upward tocontact the bushing '21 and mandrel 318'. and'repeat; the previouslydescribed cycle; There is 7 no hesitation ofupward movement by the:die-core subassemblyat position BB or the thread diev assembly atposition A-A.

' 7 Assembly mountings Referring finally to the mounting of the variousas semblies for operation, Figure 6 illustrates apreferred form of.mounting for the inventive apparatus on -,a suitab e rame- Th rame h esen i l y fourhorizonta eve s defined by, he; di ca ri v mem rs '10, hir ylinder suppor nl b rs 0a, bottom brace 10 and lower, plate vsupportmembers 16c. The horizontal levels are-joined by vertical support 82a,12, net cetera.

' offers sufficient resistance to allow seatingof R err se o he'mounti fth extrusion head s o sembly, as previously noted, extrusion head'1 9 issup pprtedvby, rod 11 which is mounted on'die carrier member 10. 'Tothetright of extrusion head 19 istshown'the:

plasticinputapparatus having flow line 47a. Thiseapparatus isconventionahand will. not be described in, detail.-; To theleft ofextrusion head 19,1mounted'on vertical support 82a. by bracket 83 isconventional; air.

The mold assembly is; also. mounted on die carrier Conventional aircylinders 85' havingv shafts; 8,6 carry platens 75 1, (the die moldsarenot:

members; 10.

showniin Fig. 67) ;mounted 011' bases 87. As is best seen; in Fig; 5,platens 75.-A have guides 83 which ride on ae sfiii r A;preferred; form,of conveyor belt system: for the removal of; blown containers is shownmounted; below die tcarrier members 19, having main belt 90 and pulleys,9,1,- and 92 which are driven by electric motor 93. (mounted onaircylinder, support member 10a) through gearred l cr 94 by-drivebelts 55and 9.6.

Referring tothemounting of the thread die core assemblyit should, benoted that wedge block 69 is fixed tQ/theshaft 97 atone-endv thereof;the other end of "shaft 97' being fixed to a:pistonI(n0t shown) ridingin conventiqflal air Cylinder, 978. Air cylinder '98 has air input 99.Hydrochcck cylinder 100 (alsoconventional) serves tqsmoioth and .bufierthe motion of the'shaft 97.

.Inthe: downward-:motion of the thread die-core assenibly away from the,extrusion head. assembly leading thnmolten tube .of plastic material;the entire thread die core, assembly halts at level 'AA;while molds 75close having threaded portion by lock nut 106. Pin stop rod 104 isrotatably journallcd at its upper end in upper plate. 107, havingupper'hole 108 therein to permitmotion of the die core sub-assemblytherethrough. Rod 104 is also rotatably journalled at its lower end inmounting block 1109 fixedly attached to lower plate 11% having lowerhole 111 therein to permit motion of die-core subassernbly therethrough.Lower plate is mounted 'on horizontal. plate support member 100. Springloaded plunger 112, is mounted in arms 102 to delay disengage-- ment ofpivot pin extension- 53a. Knurled vadjustment screws 113 cooperatingwith lock nut 106 adjust the'relative'height of stop block 103. J

Referring now tov Fig. 6, wedge block guide rods 114 are also mountedwith lower endsfixedinlower plate lit? and are fixedly attached at theirupper end to upper pla e 197. Wedge block guides 115 are slidablymounted on rods 114 and guide the die-core sub-assembly in its motiondownward from the pointA'-A to points 13-3 and C C, The stopping, of'thedie core sub-assembly at point (3-0 is accomplished and determined bystopping the, piston in air cylinder 98. Cylinder 98 is attached tolower plate 110 by bolts 116 through plate 117. When the die coresub-assembly is returning from point C- C .to point A-A after thecontainer is blown and removed from the mold, it picks up thedie:holdersub-assembly'and moves up toward bushing 21. Springloaded'plunger 112 wedge block $9 in the die holder lower arms 43!).

From the foregoing it will be seen that thisinvention is one welladapted to, attain all of the ends; and objects hereinabove, set forth,together with other advantageswhich are obvious and whichflare inherentto the structure and method.

It will be understood that certain features and'subcombinations are ofutility and not to be employed with: out reference to other features andsub-combinations. This is contemplated by'and is within the scope of theclaims. a ,7

' As many possible embodimentsmay be made of the invention withoutdepartingnfrom thescope-thereof, itis to be understood that allmatter-herein set forth or shown in the accompanying drawings is to beinterpreted as-illustra tive and not in a limiting sense. 7

Having thus'described' my invention, 1 claim: 7

1. In apparatusfor forming hollow containers-with pro?" molded, fmishedneck sections includingan extrusion head assembly comprising a body;having 'a cavity therein, a plastic inlct opening into said cavity, aplastic extrusionopening out'of said cavity, and a mandrel positionedwithin saidcavity and extending at least closelyj adjacent the extrusionopening, the improvement which comprises a thread die core assemblymovable to and from said extrusion head assembly to receive plasticmaterial therefrom'and draw a tube of plastic therefrom, said thread diecore assembly having a thread die subassernbly and a die coresubassembly, the thread die subassembly, comprising a longitudinalpairoi die'membersincludingmating molding faces at one end thereof, thepair of die memhers pivoted at a point along their length, and having:outwardly angled legs at the end opposite the mating 'mold ing faces,whereby-to engage the. mating moldingtfaces when the angled legs areapart and separate the mating molding faces when the angled legs aretogether, the-die" core subassembly including a1diecore irisertable' between said mating molding faces to define therewith a container.neck-forming plastic lreceivingannulus and removablei therefrom,';. andmeans cooperating with the 9 thread die subassembly to force engagementof the mating molding faces when the die core is inserted therebetweenand to force disengagement of the mating molding faces when the die coreis removed therebetween.

2. Apparatus as in claim 1 wherein said means cooperating with thethread die subassembly to force engagement and disengagement of themating molding faces comprises rollers mounted on said outwardly angledarms, said rollers engaged by camways fixed relative said die core andhaving angled tracks.

3. Apparatus as in claim 2 including a wedge block fixedly attached tothe lower portion of said die core, said wedge block figured so as toengage the inner surfaces of said outwardly angled legs when said diecore is positioned relative said mating molding faces to define saidcontainer neck-forming annulus, whereby to lock said mating moldingfaces relative said die core.

References Cited in the file of this patent UNITED STATES PATENTSHoffman Oct. 4, Lindemeyr Apr. 3, Glaspey July 22, Howard May 24, HobsonJune 30, Gits Sept. 26, Clark et a1. May 22, Brunet July 31, Mills Dec.18, Rowe Dec. 2, Haines Mar. 24, Sherman June 21,

' FOREIGN PATENTS Australia Dec. 18,

